SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34ba5acf8a62d2fff33c86ad25e7b1d86f58071fd98c898345215b8e0ffa4b46' 
  AND token = 'FypDMJQ8RjZqYDUbHVrmzsI44vS+11S2wRhNJiB78e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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