SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43e1ff3a68126f918db550b6a306885ea80d6a1631706c4ede0db704c23a3550' 
  AND token = 'UjsnWcH3kmSS9mOmlMROESIi7FDGXDyyhX8jQhDiI6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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