SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50ffe040ddbac100f79341081426df2ebb0b886ff845ae89550207c7db3503e6' 
  AND token = 'NbFdjmWzCcQJ4T2YLk3d3dHI/cybzqJEntAjHoKZ3Fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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