SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e4979bec3dcd42c666e6eae363f750b91c10ceffd2544b139d2b699c0180230' 
  AND token = 'uUEKbRWSggmf/Q3K8pE3683U/sVAVrqRQ2fZx2IuA8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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