SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a2c4b742d5ef2874bf5448396ae344e563b91b505fb0d5c0abdbf224bc22f03' 
  AND token = 'J1n9IGiPqlevIrSUHLA6G7o94ITxulKu2G9W3oLxCJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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