SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c51d21cebeb93eb7510a8431c68444cba92b92177cf3b6eb449eaa461f533d93' 
  AND token = 'JaQoWR2sMVX3LJG/fK8wpRQH+56lJJ/IovjOR9v0+Uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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