SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e0209b5ec21c9e5d035abca04c1aecb3eb18ac3e494b1cea5f0448f96e0f79e7' 
  AND token = 'RIuSGS8FkG69WpBx9xQrMc1JWwX2y9UFNUgdaq69EEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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