SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f90bdff150d7fbdd5bda54146c6a91315acfb5af14b95cd02ef9ba11e26bb2a' 
  AND token = 'kjBXJa51MrrWntWwQgZ7uTTsyU+8VY63R3cVnV8A/GI=' 
  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"
    }
  }
}