SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4e0d236cc2466b799bd91c637cad98a63e3cc2091435402b2025f6a55274884' 
  AND token = 'jNYAVP7e+fUAVoDvYfCwNkgdzd5OZQef/f/v8ZtuW60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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