SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5bb3b520797db39e18e4163f2b67a24108ac7d7a9f9532a7459f27902ac9e80' 
  AND token = 'qKX/f+EDC5ByqT2qPheQPFmistXjoP1VfSonwL1Dq84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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