SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfc58bea7fb3e983fec7d3cb8d3b809f8755776a14ee69576a5d9b0b398858f8' 
  AND token = 'TnKlLcId8ikOsUix/5U/figR89D11HCbjyb53b2Vbzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}