SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6d09372ff596f5412abb83ae36a66e38b3ea75cdb260dac9ccbeffff1ae22b8' 
  AND token = 'kgg3NQQeL+a+csEZXJ4G+F7xlAyVJHWFqqaNyDIsSlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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