SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8216425eb9876f834611671ccfe3f2413c8b80b94316fba389c1e68516bed15' 
  AND token = 'ALJrqGEJiCaPcyJGrETugA8CNWMKBN5b/2SGHEvvcJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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