SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e720aca9ef7d6c824a398d3af5601d021ad65606c03237c122478db9b6a23259' 
  AND token = 'cOzUZYjwguz+30hMKYGIG7a/XCUxWWZvvE+vMTibcY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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