SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '598bc6c83df5642f19767ac7f17651cf109da22b1aaacd64358048f005462970' 
  AND token = '+37XCIVBOteDWE2LHXYtclS/XEZ/2IcRRU1BjTW+f2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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