SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b2ddd7b6e571b32bd3de9547f325907c5def643388ea85c7b0314ab882b76cf' 
  AND token = '+2dK5mOK1awsJfKZLUOAiZYv0isUigzpC/P9FoqCQxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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