SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '515b54ee1ff80ef7a987dfedb6eea72ac6e16578141158409b282cecb4ef9aeb' 
  AND token = 'ZB0p9UYesdkZZG5f8jg1r8RvysB8QaEVRQpW7XNpgOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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