SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ecdf6b5a46e845befe1f6ad9116cde696968956e6b81d2b679fccdbd10e6c4e' 
  AND token = '0lWxHFMu6GN6OJAnqpcgj02fQdcMjZzbkcP15Ux3LgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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