SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2e1b157323d737e4f0f6add81faa96a98cef150f841077fc238d0db4a676844' 
  AND token = 'gkpunkT174cfxksTiLHrFdAqMdVUBtwmTT86yvfFIL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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