SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a6ad94b88f234868f26c3ff1d1f9090df78418d1cb0d0547d762694bb6e1d11' 
  AND token = 'duryA+xDcOAeDvcQQqAwCaiY+aplSwnLqJrPDorfKk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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