SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a80bd6c2ee8982a61f96dfa8d99b79c838021d551f04a7e3bffbe4fa36d638bc' 
  AND token = 'VE2gQPwZk1rNLmJHiCddeOJ/+0ygALNzMTCfwWRuU1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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