SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cd964484fabe74f495c3ee78f24b6dd80dd5099beade68b1472675690657eb6' 
  AND token = 'dLnRU6HKAvsjB5kLeNzYG+FDCsXp9ujxc/HzKgQK1P8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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