SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7471829a83dd4fdbddc5e6a6a2cbb7a00aeb2ca46766c02a3b42179611550e4' 
  AND token = 'gYtgp3LU1KOs8AUGsfVOSzLsJ/D8qfm5HjB6C0U+qpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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