SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8041a9c1e299fc99a62a68db0a138b93052ec69e8b2bef7d8cc725afb8c2775' 
  AND token = 'Emwoujp0BoxV55asv05Z+rzWEkQM+xjWoHQVxIU9N5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}