SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28371dd961659e9b437cac04729f4ac51660b3c6f4c0948faca69ba230ac0bf1' 
  AND token = '1+XjD9OGYpo2U0g/5yKBcsC5BcQweUUz64USpf4h+UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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