SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e57f8302400e94aaad2831a1136c536592ce73beca6485fdef12f973d63ad1a' 
  AND token = 'zhzvE7Wx7JU4m2GWIOAtYfuVCZBw4vNTjOashMfSCsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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