SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9287a03b5c13de16bcc57057b41902cba1786d34cdaf60ed55ffa05b51a0c120' 
  AND token = 'Wcti7WmlpCFOZLiDZCk65IpJLIjvn5pz5d4qDh7ssiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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