SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7e396509378ba95db84e7f5e8bd23e412a51d3e8caeb47e608f52636ef087d1' 
  AND token = '5HsXBSjjkYbru4pUWPv7mYi+lgprQ+jJUxWO98afGEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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