SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '376491f1e11b86ae7b52bef6690327a2a21b034ff6989aec3c6615527a507d18' 
  AND token = 'cDRPANE7IuS8w3w67L97rgdNYlacHnW0DsVhK41UQ7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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