SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e19002597803189839339bb5e5b60f6d7b47c7c8d0836dbe3144f0395feb72c' 
  AND token = '0L+QwqmX7LrCEZP3qShM4KShvsu4EZobsAwWpNpQomg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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