SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '719c467636164fa903a641a025514a1528f38bff3b73357b0be9fe50933db9ce' 
  AND token = '7Y1nuPBAvBGozVsOL2fln1PwqjCpqXaltrpZUASfLV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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