SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '03887ba4012063c050a19e3c1123f202e0fde5f6323da695192d3ebca9723b1c' 
  AND token = 'p2DfjeeidBjTIdLSC+8wRbbmYBlh8L36BWequTw2JKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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