SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7363f4ace1a4eec69fcd560bcd43066baf54300fa1517dc02df04563a48acbd' 
  AND token = 'DSq4r+nZJggt4h5HehAfpZksgddqPLHLpZ6Kf92ppCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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