SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc909e515991edd5fb78a72e1607bbce74252983abbb430c6c4ce5368f9f015' 
  AND token = 'b87mYGqM2GIk8q/z3NvpSay98Pz2o7vsDRjbN/sCOhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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