SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbd65ebdfca86149603485d775a2c1ee789888aa743037ca6a90d7ea1a22f27c' 
  AND token = '6cr/7j7hM7GBu4QHKSuU9qgKrJ1amFHPU55XVpCJuNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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