SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b69ce61a81ce5ffae81624a54d14417d9b67bb4741a0ce923380d1fe9907815b' 
  AND token = 'zdTBUpO3LQJ8vMHbmO5xm5jXRMqqrgEuh3044nKb/qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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