SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '611679f108c2b20a87aed336266d355b63ade779fd58e510a49fe1e8fa08beae' 
  AND token = 'MJeqThHVObiOFNtJ/szxzQMwD+6rb/HB6It+4GaRjOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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