SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3a7c11f603cc29e2429a24cf95454837676416fab0cc76513a7831bef34c3aa' 
  AND token = 'ljVC7xbdQPTlmM9CCeqRXHdLYxMCBN3j6ALZwGefufw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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