SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '457a1b438b573a38ecbea8d80a22a94152760d4df147fb80c752d61643611f08' 
  AND token = 'ARMKzKoOr+/5tlpM5/Z9xs8TnBGJKCDbmOkhu1O91l8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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