SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '552f4942ba29f5c01d9d137edcb558841db042965588657333dc15aaed79f754' 
  AND token = 'rOsWqr5BSvUc0kQsu792ae18lwh7nVVuPK36JNfRLwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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