SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49f4d37f6228102cc8f6587ad0288e661ac50c28fa3c91b62b17343c3de559b3' 
  AND token = 'zDVqV8l5NdvC1+YfZ7Hu9y8xJ2YK3c7OzHwi4AtR/Es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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