SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77dcca94ed66c33e4847dc921cbb95a6fb5fa2a229b268987550710f6aca2d80' 
  AND token = '4jdgUV4QjumFMlH8j4hhBKeMwtfAwu58EqSgUbdDXCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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