SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f6ed4e4a4acb92b8bd00b5636de13763bfb7946e8bfa91292eef11f11998396' 
  AND token = 'BFTss5Lm2FEpp0fznavDSTqoofNWeiSnTlZI3pqk1+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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