SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c44a38497fa3c0029314c59da895baa0216ef87dfbff71413407082e001509e' 
  AND token = 'RfXQlIfDmE6dHPORyjUjbja8zPTZ5KfMs/Gp8S711wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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