SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1e127b176fd2be03d2f751130afdb6b55ae546c53e522caa36ba8f57251f89e' 
  AND token = '9hN1nEaKJnoYU/8tpPRVRUL8+GhSsFhSyBgjiX7wYQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}