SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ac765c7a4d77ef64e625dbe40de36b871dc4b560f584e9d8ff25556bcf1a390' 
  AND token = 'sUCeSIIaIevlMMWg4em57AzLGeyhMYRLJtDcSp95YCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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