SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f73cfc1b7782fd82f0e36f05e5964ae9bc76634e20a7de489844ecc136f2d378' 
  AND token = 'wBbvdocYDaMYcl/6/RKle8kgRLnZUDjpACnM6pEffew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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