SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5ff61b2dfc5a6e3412977d85983abe807e1c910100297feb4b5d27fbae6ec8f' 
  AND token = 'nHfL3QG4qimpuC+vanViiojq8CVjIBQnlh85je1RBRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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