SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ba6d861528707bf2d3f25b1fcce368f898d6d8f63990020d9a9eb61a1e30808' 
  AND token = 'qLoiSsoyEXP6LrH3AsvsxmPdyABo/LfNLrzqKgBD260=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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