SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e726d0531e10ab37f4716ca9806282b8c0c8ffa09b71f036264dc7e5a54ab2' 
  AND token = 't5EED8jlbB6+qwYGBrGCx2l18lpAzoCjECBLGhqXiPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}