SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35481bb9bc31b3720fa9caae3de75fd8469a7cf5f4881b29f1dbf68df77e059b' 
  AND token = 'z0E0qXO+pwtYwx+FkDMJWYtrtr1SqbkZoDa1qNeKeZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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