SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5122f9bbc5e57a9e8942e23771cdf72bde455cb5b8d4e6bf328669259a310fbd' 
  AND token = 'cwGBueh27PkjVuTfwDgCRfKkIZm0itTzCAthHU42JXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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