SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3226da2e3e0a1a976743fb1ce1bb2c27c8183e1f0d39f1f98fcf8c5df4e76960' 
  AND token = 'gBFiEQmuYc7rDLSoRJUwMcmZL7xSB0FA+AqVGqHMC+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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