SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'accb73b071bea6ab99e1eeb9505bf4256796992d6156859aa73a6a1b7a87addc' 
  AND token = 'sbCiML/oZDR9aWKuzhBnBjIgG1SVfF81elFiouZYCsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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