SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c0b67f4803c979275b9dcdd5642723231b4f4783c4c15eff60473e154c637ad' 
  AND token = '6IDIX6wXUvKNXvWSFYvl591LYL9r805ALpdFz8IhN2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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