SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19a6f7daba2787048f21fe9c602fab386a21a3779ee69e278407e36afd1809bb' 
  AND token = 'poSGJjF8Fy/rwyfFBgxghiNor2xzyYcrbvm3WmcL5TQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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