SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9125fe5c69590c7e8413ddec3b7caa32fe9540c500a3006cce2f66806f747ad' 
  AND token = 'Yx6PHWiN0VCPzCm9L9id1AqRg+ZtAGHRq9BhthgOV4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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