SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92e25a614ddc44988f9def38452e1215e4dce6f4711d6274ad605fbbb7758106' 
  AND token = 'hXdS4DP4l24OWduYrUubFZ4pSgC0ZwNCsJZsgfYXToI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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