SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fcd6e9e98e30bf5cf47feec16ad664674db4d0b6d451bb56a57ca2ef1980d1a5' 
  AND token = 'xh2+sV72hP5UZkGCWOZmoQt6ESLZq5sHrdyIwRNeWOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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