SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8edc71b82e96b5d53957a3d3542d10372d1b43f67764c8dc31011438712c8cb' 
  AND token = 'Diat3I5oaQYYBw2OTzTMSHXhO8mqEN0TzBbOOswkcqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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