SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d3c2283ce0e26250334ff8defe4b28aa112cf3fbf28af6b36d602d9bea79cc8' 
  AND token = 'Stf0XVxcV5SQRzLh1scbDYW452wHy7QqhliJNfhij1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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