SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5779a0d58f52e1165fe2e08f6052ff6b9c50f370db49aac9541765debbed444' 
  AND token = 'DDBcLgjP5Arb2ED447x7zVWQqnCdMu/qfgTb68/TG4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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