SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '906375e84016758fe95e7ce6ce2ce54c2fd541a18caf60b4a48e65ca25d62752' 
  AND token = 'SxZIrbNzL+El9XJVXFZvsS6f/mkHzIsn7Ljj0bQOpPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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