SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a309250c749c8eab57c2e93727df8520ca9cb87ddeb1896fd48598fee3574aef' 
  AND token = 'grepaQ7haVCFawSvN4jZldVMGkKyyjFoMc6YhTEQc8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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