SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e9bcbcb63509857d7887e00993b7ece697c6e5d495f5724ec67a906d3a1941d' 
  AND token = 'MihIXQLDjFeEHDGzVj7X3GEsvQ/GdxW2JmAHKucINes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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