SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bb07404c046ddf4caedd357b720e9d5e04a91fcc85eba437ec91454281e9e82' 
  AND token = 'hN0UeJ0ESqvZtkOjkUrBFaOssyDlud/bNoxoGqei31g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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