SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b983aff4c6d4ccc078e3785d19ef72812c3448440f5c7b4c2e3fd250f875f299' 
  AND token = 'lgPGsN1opUFUSaH+0tBnYM2bzo9y6z8NgqwimgBQqVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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