SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cd826611ffda02c1e155f676ce6fa24b91694453771eba1b6efa8af1a65deb1' 
  AND token = '0bMtTutXtvFVIozPquDObv6r4vF4l6PDFPdrEteBYyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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