SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192f695eea09ca81d295f546242493f589723810fa7e14ed7bff5617ece44e2b' 
  AND token = 'nQcFbAmOJp5SHyuNyapzFYadMBBhIfwrwShGXnj5g2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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