SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '537c36cedc3513bdcb0a3b188b38934bf269acfd974ef4272c5c4db0f1ca9f48' 
  AND token = 'iZNNxaOi+2f2o6WnC4AoreTkMjHs0KYVFxawOPoYdws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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