SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c852c72a8ddc031fc7dbdc01a9922da36cbb1d6958977a81c58477246993cb9e' 
  AND token = 'LWQggVFq5cR0LbxWHyIed57SDxxebH9yHhyFvL1IoY0=' 
  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"
    }
  }
}