SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b690f0b065bb7f5aff347373f9946fab80c4e7cb029481a874789120ff99a63c' 
  AND token = 'egOF1Ht9WFPHewpwKCohLxVznmWVHluidTkBkqowt4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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