SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32a8cd728d60e4683a3fd2b2e62b4b727b51e8c8a83c3aa878f99411ef998bc8' 
  AND token = 'FhMNVxjUGZR36aZUYVM7CabeOUFH+x15aMVHr8QpKrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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