SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0aff04b124aedc03999f696baf975aaf38ec4e66e97e60fe8077305e964eae6' 
  AND token = 'EFqFmRuDzysFE8x2fs2OzxOmedCYReyoJaeIv/jGaQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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