SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66be8c41ca56eb93981688a16e2bce5bebc233d32195cbb44bc7b4cecd6ec602' 
  AND token = '5UGM3we2R1gbYCk75dDmRk0p+qDPDrDiPTBjc/mLQoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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