SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee62a699de83f73fc6d02d7d839cdddcf1cd3d8720b46876c8cb642952aa2bc1' 
  AND token = 'RHgE7gCPDniIoRE6dmkUerhWEMtdYZaepiqPTJWY0BE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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