SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66b242230b5fa2865fe1d607a1616a8df23aa746df00efe9992a828b06fc5da8' 
  AND token = 'pqNN8bZlFS7IB5qU2GoSFsqd/FYpmW04vULW49QG3GE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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