SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7661a53eab1c7e184afb6a0ea338c2242e5031a1624784f9459787c7b1411e20' 
  AND token = 'BfdKBMfARCluuts+8vPCpbSmq2wg7TZL7lA/7qHyWxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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