SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '611c8cdaa048ea18c4d627570d1f36e71483af6c6a2863019fd50899a978632a' 
  AND token = 'RiN/THKt71In5D2EFEAOYIzQ+39NE2dVnAlS1Dts0Ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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