SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb9f17e916e79d5eaa0078f87e2237ece1357ff5480803f96fbddf568d00f19f' 
  AND token = 'tbyL/YxDQ6cTPrcvhyo15JCAScWTE/7dDaQ5ah0PWCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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