SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f20cf18f3f69ee2409fe2591bbc6003eff54b12abdedbafdb574bde3fc95a1c' 
  AND token = 'B0DL4eRj0qds9AJVXqyx5sLjio77G3XITO9bI1VIvOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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