SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c342380d4b4b2df02c9010b80f97fe5a1eab3399fbf3190573225541f7787c' 
  AND token = 'WvJT/Z6WzlVzGn/8iEcwYW2PJgI4htTNGm0YUnge9rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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