SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d5f9261be2a264b21b9b644d4933f39b838b608ef65db40c2a8494ee2710d0' 
  AND token = 'ALepQEcG+ZyqPB+k7/POugKnLTdHWZ9vGVuY42HGk9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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