SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b438f9735b68817118b1a495452f77ec4d5dbd5cf4ccac9e79ff7281563c6998' 
  AND token = 'PZ4gc4BTnGLzwpkY7+B6DEyy0lVJLLtbJ1eOaUXNMeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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