SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0991e2231cbc6528f4ebcadb88a76851d991e676de9215f6dba9b35748c87cf3' 
  AND token = 'PsSOO4PJr9l4iK8hE5k89q/0vxx/gRQtW+fLlRmV/2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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