SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cae54bee7cc58f9caef88f54942fe1247a6a3bcd32fcdd7c70b9ccc54beeddb1' 
  AND token = 'UBHlVCwmfpL/h2YUORnVj7Hk+75FEgJHIO2q9znciUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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