SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f1b7929a926be9e371a5ef7b8322df4ade3ca0de9c4e2de76d17aed4d0fcc2ee' 
  AND token = 'dW0ZcIhPt3TQAMJu4ycqwVafCMMirZs1zSPEwoGrWCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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