SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83338ae56af26609f0d279b4f118b3611b7bce66b5f13c62af556c46f2b027da' 
  AND token = 'pgKrL1PcV/kxSAd9zjYvVGftsDn4p+8cgir8IfhimTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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