SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84af0ef8f0fe48dfe729a7a5ae908a9819cc73a155dfacc3ea0e994a09a48de1' 
  AND token = 'TmsCouhV3m6MHdEhWFq+ml9f6yTZIJIDCmnMhrepy0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}