SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6f716f876f4a5e9c084f6b2545caf0df389c4e112c0bbc272b15e6b0d932d74' 
  AND token = 'VOnagYDgkZ3XKrVwsllqUrk3TRavDYJ3e/narpYdR9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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