SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ca9de86046757f13de75467c876160a2fa14684b231c26eedefd53d8bd08c2' 
  AND token = 'g6lVfhxb0gOrs9N/OgSvdnIFpqItEYziLY8lKgQlFaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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