SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea20a7b24f171e08232766d8ccd2b71587a9b4e5bf73fd3bd532ca0a7b99f757' 
  AND token = '8h+URcHq1XpUOUmOojQHgR/puOuyYM/RSKRlpndluZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}